Is there a way to render one layer
Yes, there is. In the properties panel ( to the right ) hit the button in the top bar next to the render setting (next to the camera) which looks like two pages. This is called the Scene settings. Under layer, you can choose which layer to render. Hope that helps :). 

Edit: There is one more thing you can try. In the top right where it shows the different objects in the scene, you can’t hit the camera so they won’t be visible in the render. I’m not sure if this will preserve lighting though.